@gbaggett75002 That would have to be brought up, but it is simpler to merely have the raw materials and turn them into what is needed than to anticipate exactly what will be needed and bring that many finished products. As for the supply chain for materials and everything else, NASA is working on that in conjunction with MIT. I wrote a blog about it that is posted here.

I was thinking exactly the same thing. Where are they going to get the thermoplastic or metal used as the source material?

I would think that if a manufacturing station were to be parked in the asteroid zone between Earth and Mars and use those rocks as the source material, that would eliminate that one problem. Silicon and Aluminium for free (almost).

Then comes energy. Now if they could only print solar cells then NASA could print solar cells the first half and then print anything else from the materials found in the asteroids the problem is solved... You still need the energy to melt and process the asteroids...lol.

This sounds like an excuse to build a "death star" ship...not to become a planet destroyer but as a ship builder. Even the Star Trek Enterprise was built in space.

Maybe Elon Musk will see the benefit of building his own manufacturing station in space to sell parts at an hyperinflated price to whomever wants or can get them.

In 2007 the ISS Solar Array Alpha Rotary Joint (Sarj) Bearing failed, disabling sun-tracling motion of half of the solar panels. The joint was redesigned, and replacement parts were manufactured on earth, they were installed on a later flight to restore full electrical power, and a special grease was applied to improve lubrication. For a realistic test, try fabricating replacement parts for this rotary joint. The joint is metal, so it will have to be done with the improved printer. Incidently, this is a large joint. The entire assembly including bearings, gears, motor to rotate the panels has long dimension of about 10 feet.

@Bert22306 Currently, 3D printing can be done with a number of materials, but moon dust is not one of them, as far as I know. Taking the materials from the moon, etc., might open one to charges of plundering space bodies, so I'm not certain they want to go there at this point. For now, the idea is that if you take the substances that can be 3D printed, which include plastics, as well as metals and ceramics, you'd have options to make what you need even if you did not foresee needing it years before when the original supply list was put togehter for the expedition.

@_HM no one is suggesting that we pollute space. What is printed on the test run will be returned to the earth. And what is printed in future is meant to be put to use -- the same way equipment manufactured on earth would be.

I would agree that it's ultimately going to be necessary to build things in space, we'll still need the raw material. So something will have to get shipped up there regardless. And it goes without saying, any manufacturing will involve waste, so the weight of the raw material will be more than what you'd ship up as finished parts. If we're talking about a station on the moon or Mars, at least in principle, one might think of using raw material from those locations.

What I'd really like to see is space vehicles or space stations that create a 1g environment for people, before talk about staying up there for extended periods of time. These structures can still provide the 0g environments, if these are needed. But really, people do need that 1g if they expect to spend any significant time out there, and still hope to come back to earth.

@Max, yes, I'm very optimistic about it. While on earth it's often used just for novelty items, it can also be amazingly useful in medicine, aviation, and industry. And in space, as I said, it can prove a real game-changer for supply chain planning.